A wide variety of attaching systems and methods are known in the industry for mounting chucks to drive spindles of power rotary tools. For example, threaded connections, tapered bore systems, coupling devices, etc., are well known and used in various applications. An essential feature of each mounting system is, however, that it securely mounts the chuck to the drive spindle so that the chuck is precisely aligned axially with the drive spindle rotational axis and is not allowed to move radially relative to the spindle so as to minimize run-out in operation of the power tool. The chuck must be secured to the drive spindle in the axial and radial direction to ensure proper operation of the rotary tool and tool bit.
With conventional threaded mounting systems, the interengaging threads between the chuck body and drive spindle are primarily responsible for securing the chuck device in the radial and axial direction. However, due to the machining tolerances in defining the threads, a certain amount of "play" always exists between the threads. This "play" can contribute to imprecise rotary operations, particularly in high speed and high precision applications such as routing. Additionally, operational stresses are absorbed by the threads between the drive spindle and chuck body, which may lead to binding of the chuck on the drive spindle, or other distortion of the threads.
The present invention relates to an improved system for mounting a chuck device to a drive spindle wherein the convenience and speed of a threaded coupling system is utilized without the drawbacks noted above.